Some of the packs are quick to dissolve in water, but that can be a problem if you have wet hands.

And there is also a safety concern. The American Association of Poison Control Centers has issued a warning about pack detergents. It has received more than 1,000 reports of children being injured or sickened by them.

"As with all household cleaners, it's important to keep them out of children's reach," said Dan DiClerico of Consumer Reports.

As for how well the packs clean, Consumer Reports tested using swatches that had been soaked with tough-to-remove stains like wine, as well as grass. The swatches are washed along with a full load of towels. Then a machine analyzes the results.

Only one pack detergent, Tide Pods, cleaned well enough to earn a Consumer Reports recommendation. It costs 22 cents per load. You can use it in both front- and top-loading washing machines.

However, another Tide detergent, a powder, does an even better job of cleaning. It is the Tide Ultra Plus Bleach for about the same price. But it can only be used in high-efficiency washers.

If you have a conventional top-loader, Consumer Reports said consider Powder Laundry Detergent Ultra Up & Up from Target. While it doesn't clean as well as the Tide detergents, it costs half as much.

As for the poison risk posed by the laundry pods, Procter & Gamble said it will put a double-latch lid and a bigger warning on its canisters. Other detergent makers are re-evaluating their pod packaging.